The presence of nitrogenous compounds in wastewater liquids poses many environmental problems. Storage and degradation of wastewater containing protein or amino acids result in the formation of ammonia. Ammonia can be released into streams and rivers and thereby threaten aquatic life. Ammonia gas may also be discharged to the atmosphere from holding ponds or treatment facilities, resulting in environmental and public health concerns. Atmospheric ammonia forms small aerosol particles that have been linked to significant public health problems.
Normally, ammonia is removed from water through aerobic processes, such as nitrification followed by denitrification. Nitrification and denitrification can remove a very high percentage of the ammonia. Through such processes, ammonia is returned to the atmosphere as nitrogen gas. However, the nitrification and denitrification processes produce nitrous oxide, a greenhouse gas.
The processes of denitrification also results in a lost opportunity to recover nitrogen that can be used as compost or fertilizer. Typically, ammonia fertilizer is made through the combustion of natural gas with air, which is known as the Haber process. Creation of ammonia fertilizer via this route is expensive, and produces carbon dioxide. Carbon dioxide is also a greenhouse gas.
An alternative process that recovers a portion of the nitrogen from waste liquids is desirable from both an economic and an environmental standpoint.